“It felt like, ‘I’ve done this thousands of times before,'” Collins said after Brooklyn’s 108-102 victory against the Los Angeles Lakers on Sunday night. “You go to the scorer’s table, you hear what the play’s going to be for the next offensive play and you go out there. Once you’re out on the court, it’s about basketball. It’s what I’ve been doing for almost three decades.”

What a day! Great win tonight @BrooklynNets over my hometown @Lakers. Thank you to everyone who has supported me throughout this journey.

Collins entered the game with 10:28 left in the second quarter and the Nets leading 35-26 after Nick Young made the first of his two free throws. The crowd welcomed him with a nice ovation when public address announcer Lawrence Tanter introduced him.

“I thought it was great,” he said. “Being an L.A. kid, I can’t think of a better situation, playing for the Nets and playing here, and getting the win. I’m just glad Kobe and Shaq weren’t out there.”

“I had him as a teammate last year and he is much needed around here,” Pierce said.

“In the society we live in, this was going to happen eventually,” Pierce said. “He is a guy that is going to be able to open up the door for athletes around the world. It doesn’t matter your race, gender or sexuality because it’s about being part of a team and caring for one another. Every guy in here does their own thing and so be it. In this sport everything is magnified and it’s great to have him here to open up the doors for so many athletes.”

The 35-year-old center revealed at the end of last season he is gay, but he was a free agent and had remained unsigned.

Collins was aware of the magnitude of his signing, but repeatedly said he was most concerned with learning the Nets’ schemes.

“Right now I’m focusing on trying to learn the plays, learning the coverages and the game plan and the assignments. So I didn’t have time to really think about history,” Collins said at a crowded news conference less than an hour before tipoff.

“The pressure is playing in an NBA game tonight and last time I played in an NBA game was last April,” Collins said. “So I think that’s enough pressure right there.”

Brooklyn Borough President Eric Adams called the Collins signing “a milestone for all Brooklynites to celebrate.”

“He began his career with this team, helping it win its first Eastern Conference titles in back-to-back seasons, and was beloved by teammates and fans for his professionalism and leadership,” Adams said in a statement. “Last year, he became the first active male athlete in one of America’s four major professional sports to publicly identify as gay. In doing so, he became a trailblazer for the LGBT community and a role model for every community, especially our young people. Today, Brooklyn is truly proud to be Jason’s hometown team, as he has brought us pride both on and off the court. I wish him the best of success in helping to bring our borough its first sports championship in 59 years. Let’s go Nets!”

With a need for another big man, the Nets turned to the 7-foot Collins, who helped them reach two NBA Finals in the early 2000s.

“The decision to sign Jason was a basketball decision,” general manager Billy King said in a statement. “We needed to increase our depth inside, and with his experience and size, we felt he was the right choice for a 10-day contract.”

The Nets are owned by billionaire Mikhail Prokhorov of Russia, where a law banning so-called gay “propaganda” was the subject of protests and controversy at the just-concluded Sochi Winter Games.

Should be noted as well that Mikhail Prokhorov campaigned for gay rights in Russia during his presidential bid.

Collins has played 12 NBA seasons, including his first seven with the Nets, when they were in New Jersey and Jason Kidd was their point guard. Kidd is now the Nets’ coach and Collins has been a teammate of several other current Nets.

“Jason told us that his goal was to earn another contract with an NBA team. Today, I want to commend him on achieving his goal. I know everyone in the NBA family is excited for him and proud that our league fosters an inclusive and respectful environment,” Commissioner Adam Silver said.

The Collins signing comes as Michael Sam, the SEC co-defensive player of the year from Missouri who recently revealed he is gay, is taking part in the NFL combine. Sam’s on-field workouts in Indianapolis are scheduled for Monday.

Collins was asked if he felt the tide is turning regarding gay players coming out, including Sam.

“I hope so. What Michael said was it was about him being a football player and me being a basketball player, and going out there and trying to help our respective teams win,” Collins said.

He played 38 games last season with Boston and Washington and averaged 1.1 points and 1.6 rebounds in limited minutes. For his career, the 7-foot Collins averages 3.6 points and 3.8 rebounds.

Collins’ announcement last spring was followed by numerous NBA players insisting he would be welcomed in the locker room. Collins has played for five other teams and is respected inside and outside the league — he attended the State of the Union as a guest of first lady Michelle Obama.

Former Suns player Kevin Johnson, now Sacramento’s mayor, said he saw Collins two weeks ago at the White House “and I thanked him for his courage and being strong and wished him well and to keep fighting hard.

“I think it’s incredible for him. I think it’s incredible for the league. If I’m on the Nets, my commitment is I want to get in the playoffs and I want to go far. All that is fine, but I need him to win games and I think he’s up for that challenge.”

The Nets had an opening for a big man after trading Reggie Evans along with Jason Terry to Sacramento on Wednesday for guard Marcus Thornton. King said Thursday that Collins would be among the players they would look at, insisting they wouldn’t be concerned about any extra attention the signing of Collins would provide.

“We’re going to bring in a basketball player,” King said. “It’s not about marketing or anything like that.”

The Nets posted a photo on their Twitter account of Kidd watching Collins sign his contract, encouraging followers to retweet it to welcome Collins to Brooklyn.

Collins is third in Nets history with 511 games played, and also ranks in their top 10 in minutes played, and offensive rebounds and total rebounds. A limited offensive player, the Nets hope he can still provide a presence defensively and on the boards.

“I know Jason Collins is a competitor. One thing I know about him is he fouls very hard,” Miami’s Dwyane Wade said with a laugh. “He’s one of those tough veterans. I’m sure he’s happy to be back playing in the league. Welcome back.”

Since making his announcement last year, “Life is more exciting for me,” Collins said. “I mean, I don’t have to hide who I am and I can be my normal self. The past 10 months have been incredible. I’m making new friends, hearing different people’s stories, sharing experiences. It’s just been an overall positive.”

Collins grew up in the San Fernando Valley area of Los Angeles and has a house here, so there was some normalcy to his day.

“It was pretty easy for me just to come to the game tonight,” Collins said, “drive down the 405, take the 10 and get here in 20 minutes.”

Hours later, he was helping get his teammates open and contributing to a win. He said his favorite moment was hearing Jordan Farmar of the Lakers complain that he had set an illegal pick.

“I know that I can play in the NBA and it felt good to be out there tonight,” Collins said.